Highlighting keywords in PHP search script - php

Question

I have a PHP search script that queries a MySQL database and then parses the results through HTML to allow CSS styling. I want the script to highlight all of the keywords in the results that the user has search for. How can I do this with PHP?
My PHP script is:
<?php
mysql_connect("localhost","username","password");
mysql_select_db("database");
if(!empty($_GET['q'])){
$query=mysql_real_escape_string(trim($_GET['q']));
$searchSQL="SELECT * FROM links WHERE `title` LIKE '%{$query}%' LIMIT 8";
$searchResult=mysql_query($searchSQL);
while ($row=mysql_fetch_assoc($searchResult)){
$results[]="<a href='{$row['url']}' class='webresult'><div class='title'>{$row['title']}</div><div class='desc'>{$row['description']}</div><div class='url'>{$row['url']}</div></a>";
}
if(empty($results)){
echo 'No results were found';
} else {
echo implode($results);
}
}
?>

Answer 1

Simplistically you could adapt the loop here:
$searchvar = trim($_GET['q']);
while ($row=mysql_fetch_assoc($searchResult)){
$description = str_replace($searchvar, '<span class="highlight">'.$searchvar."</span>", $row['description']);
$results .="<a href='{$row['url']}' class='webresult'>
<div class='title'>{$row['title']}</div>
<div class='desc'>{$description}</div>
<div class='url'>{$row['url']}</div></a>";
}
To make it a little better:
$searchvar = explode(" ", trim($_GET['q'])); //puts each space separated word into the array.
while ($row=mysql_fetch_assoc($searchResult)){
$description = $row['description'];
foreach($searchvar as $var) $description = str_replace($var, '<span class="highlight">'.$var."</span>", $description);
$description = str_replace($searchvar, '<span class="highlight">'.$searchvar."</span>", $row['description']);
$results .="<a href='{$row['url']}' class='webresult'>
<div class='title'>{$row['title']}</div>
<div class='desc'>{$description}</div>
<div class='url'>{$row['url']}</div></a>";
}
The benefit of the second one there is that if a user types in "ipod toudch yellow" you will be searching for "ipod", "toudch" and "yellow" which would negate the type and make the results more general.
You would need to exchange the single:
like '%query%'
with
foreach(explode(" ", trim($_GET['q']) as $searchvar) $where[] = "like '%$searchvar%'";
$wheresql = implode(" OR ", $where);
to get each search "word" to be looked for in the sql or you will have a limited search with a unrelated highlight.

Answer 2

i also found this solution to highlight each word of the results:
$text = $searchresults;
class highlight
{
public $output_text;
function __construct($text, $words)
{
$split_words = explode( " " , $words );
foreach ($split_words as $word)
{
$text = preg_replace("|($word)|Ui" , "<b>$1</b>" , $text );
}
$this->output_text = $text;
}
}
$highlight = new highlight($searchresults, $keywords);
echo $highlight;
In case that could help,
Regards,
Max

Answer 3

you can use regex or simply str replace to look for a particular string and add a span around it:
while ($row=mysql_fetch_assoc($searchResult)){
$str ="<a href='".$row['url']."' class='webresult'>";
$str .="<div class='title'>".$row['title']."</div>";
$str .="<div class='desc'>";
$str .= str_replace($query,"<span class='hightlighted'>".$query."</span>",$row['description']);
$str .="</div><div class='url'>".$row['url']."</div></a>";
$result[] = $str;
}
now the css:
span.highlighted {
background-color: yellow;
}

Answer 4

You can use str_replace. For each keyword the user uses, put it into the $search array, and also put it into a $replace array, but surround with with a classed span tag in the latter, which you can style with CSS later. For example:
$search = array('apple', 'orange');
$replace = array();
foreach ($search as $word)
{
$replace[] = "<span class='highlight'>$word</span>";
}
$string = str_replace($search, $replace, $string);
EDIT: assuming that $query just contains keywords delimited by a single whitespace, you could get the search array this way (with explode),
$search = explode(' ', $query);
Or, if you want to add more complex logic for processing the keywords out of the $query variable (like if you use query operators like +), you could use a for loop:
$queryTerms = explode(' ', $query);
$search = array();
foreach ($queryTerms as $term)
{
// do some processing of the $term (like delete "+"?)
// ...
$search[] = $processedTerm;
}